/*
 * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package com.sun.corba.se.spi.orbutil.threadpool;

import java.io.Closeable;

/**
 * This interface defines a thread pool execution service.  The ORB uses this
 * interface, which preceeds the JDK 5 ExecutorService.  Note that the close
 * method must be called in order to reclaim thread resources.
 */
public interface ThreadPool extends Closeable {

  /**
   * This method will return any instance of the WorkQueue. If the ThreadPool
   * instance only services one WorkQueue then that WorkQueue instance will
   * be returned. If there are more than one WorkQueues serviced by this
   * ThreadPool, then this method would return a WorkQueue based on the
   * implementation of the class that implements this interface. For PE 8.0 we
   * would return a WorkQueue in a roundrobin fashion everytime this method
   * is called. In the future we could allow pluggability of  Policy objects for this.
   */
  public WorkQueue getAnyWorkQueue();

  /**
   * This method will return an instance of the of the WorkQueue given a queueId.
   * This will be useful in situations where there are more than one WorkQueues
   * managed by the ThreadPool and the user of the ThreadPool wants to always use
   * the same WorkQueue for doing the Work.
   * If the number of WorkQueues in the ThreadPool are 10, then queueIds will go
   * from 0-9
   *
   * @throws NoSuchWorkQueueException thrown when queueId passed is invalid
   */
  public WorkQueue getWorkQueue(int queueId) throws NoSuchWorkQueueException;

  /**
   * This method will return the number of WorkQueues serviced by the threadpool.
   */
  public int numberOfWorkQueues();

  /**
   * This method will return the minimum number of threads maintained by the threadpool.
   */
  public int minimumNumberOfThreads();

  /**
   * This method will return the maximum number of threads in the threadpool at any
   * point in time, for the life of the threadpool
   */
  public int maximumNumberOfThreads();

  /**
   * This method will return the time in milliseconds when idle threads in the threadpool are
   * removed.
   */
  public long idleTimeoutForThreads();

  /**
   * This method will return the current number of threads in the threadpool. This method
   * returns a value which is not synchronized.
   */
  public int currentNumberOfThreads();

  /**
   * This method will return the number of available threads in the threadpool which are
   * waiting for work. This method returns a value which is not synchronized.
   */
  public int numberOfAvailableThreads();

  /**
   * This method will return the number of busy threads in the threadpool
   * This method returns a value which is not synchronized.
   */
  public int numberOfBusyThreads();

  /**
   * This method returns the number of Work items processed by the threadpool
   */
  public long currentProcessedCount();

  /**
   * This method returns the average elapsed time taken to complete a Work
   * item.
   */
  public long averageWorkCompletionTime();

  /**
   * This method will return the name of the threadpool.
   */
  public String getName();

}

// End of file.
